The numerous flight encounters by Tu-95 Russian Bear H bombers prompted the scrambling of U.S. jet fighters on several occasions, and come amid heightened U.S.-Russia tensions over Ukraine.

Also, during one bomber incursion near Alaska, a Russian intelligence-gathering jet was detected along with the bombers.

“Over the past week, NORAD has visually identified Russian aircraft operating in and around the U.S. air defense identification zones,” said Maj. Beth Smith, spokeswoman for U.S. Northern Command and the North American Aerospace Defense Command (NORAD).

Smith called the Russian flights “a spike in activity” but sought to play down the threat, stating the flights were assessed as routine training missions and exercises.

The bomber flights took place mainly along the Alaskan air defense identification zone that covers the Aleutian Islands and the continental part of the state, and one incursion involved entry into Canada’s air defense zone, Smith said.

The Russian strategic aircraft included a mix of Tu-95 Bear H heavy bombers and Tu-142 Bear F maritime reconnaissance aircraft, she said, adding that one IL-20 intelligence collection aircraft was detected during the flight incursions over the past week to 10 days.

Perhaps most worrying...

A defense official disagreed with the spokeswoman on the increased bomber forays. Russian strategic nuclear forces appear to be “trying to test our air defense reactions, or our command and control systems,” said an official familiar with reports of the incursions.

“These are not just training missions,” the official added.

“Additionally, we have seen significant Russian strategic aircraft deployments in the vicinity of places like Japan, Korea, and even our West Coast,” Haney said at a defense industry breakfast.